Method of mining boron compounds



Patented Dec. 18, 1928.

HENRY BLUMENIBERG, JUL, 01' L08 LNGELES, CALIFORNIA.

METHOD MINING BORON COMPOUNDS.

ll'o Drawing.

My invention relates to a process of mining boron compounds, especially kernite (N 11 13 0,) containing from 2 to 4 molecules of water of crystallization, as compared with borax which contains molecules of Water. Kernite occurs in lar e underground deposits at several places in California and sometimes associated with calcium boron com ounds, such as coleman- 10 ite (2CaO.3B O .5I O) and ulexite It is anobject of this invention to provide a method whereby the kernite may be 15 quickly and economically mined and my process is based on the discovery that when the kernite deposit is treated with a solvent under heat and pressure, preferably with an alkaline solution of the alkali metal salts or compounds, the kernite is rendered soluble by being converted into a meta-borate which ma then be pumped or lifted to the surface 0 the ground and a ain treated to form borax which is crystal ized out from the mixture and the remaining mother liquor containing the alkaline reagent is used in a new cycle of operation in dissolving the kernite.

' My invention consists in the steps of the process hereinafter described and cla med. In carrying out my process any suitable apparatus may be used whereby means are provided to force a hot solution of the reagent into the boron de osit underground, with means for lifting t e dissolved boron minerals with the reagent from the deposit to apparatus above the ground for separating the mined borax and using the reagents recovered in a new cycle of operation. For 40 instance an apparatus such as disclosed 1n my patent for process of mining insoluble boron compounds, Patent N 0. 1,636,456, granted July 19, 1927, or in my U. S. patent for a method of mining soluble boron compIounds and the like, No. 1,649,385, granted ov. 15, 1927 may be used.

I prepare a 5 to 15 percent solution of sodium carbonate and heat'the same to 200 degrees F. or hi her prior to its introduction to the kernite eposit, of which there are deposits in California at a de th of 800 feet. The sodium carbonate so ution may, if desired, be further heated b the introduction of steam which may e conve ed u by means of a pipe to the deposit. he sodium carbonate will cause the slowly solu Application filed October 24, 1927. Serial No. 228,504.

blekernite to go into solution and will also disintegrate and render soluble to a large extent calcium boron com ounds which may be associated with the cernite. The reaction taking place between the kernite and sodium carbonate is as follows:

It should be noted that the sodium metabora-te is formed, which is highly soluble, and which will not crystallize out even when the solution is of a gravity of 40 B. Ordinary borax is, as is well known, only slightly soluble in cold water and has a tendency to crystallize out from hot solution on being cooled, thereby causing considerable inconvenlence in handling the borax solutions. I overcome this difiiculty by converting the sodium bora-te into highl soluble metaborate in addition to great y increasing the solubility thereof.

As disclosed in my two patents above referred to, it is advisable to use the means described in said patents for maintaining the solution of the boron compounds, as they are belnggiumped up from the deposit to the surface 0 the ground, in a hot condition.

The solution is now treated with carbon dioxide in excess when the meta-borate is converted into normal borax in accordance with the following equation:

4NaBO 1OH O 200 Na,B,O,.1OH O M1 00 The borax, especially on cooling the mixture, will crystallize out and is removed by filtration or any other suitable means and the mother liquor containing sodium carbonate is used again in a new cycle of operation.

In lace of sodium carbonate, bicarbonate may e used, also sodium hydroxide and the corresponding potassium compounds but sodium carbonate will be preferred on account of its economy.

It should also be noted that the solution of sodium carbonate reacting on the kernite of the deposit is under a hydrostatic head, increasin enormously the pressure which greatly facilitates the reaction of the reagent on the boron deposit.

\ As stated above, the best results are obtained by using an alkaline solution, however, my invention is not limited to the use of suchsolution but water alone as a solvent may be used. I have discovered that the kernite will 0 into solution in the form of a mixture oi meta-borate and tetra-borate in which condition it may be easily raised or pumped to the surface and treated in the same manner as when the alkaline solution is used.

Various changes may be made by those skilled in the art in the steps of the process as described and claimed.

I claim:

1. A process of minin deposits of boron compounds containing ermte comprising subjecting the deposit to an alkaline solution of a compound of an alkali metal to convert the kernite to an easily soluble meta-borate and causing said meta-borate to g: in solution, and removing said solution om the deposit.

2. A process of minin deposits of boron 2 compounds containing ermte com risin subjecting the deposit to a solut1on o sodlum carbonate to convert the kernite to an easily soluble meta-borate and causing said meta-borate to o in solution, and re- 25 moving the solution rom the deposit.

3. A process of minin deposits of boron compounds containing ermte comprisin subjecting the deposit to a solution 0 sodium carbonate under heat and pressure 30 to convert the kernite to an easil soluble meta-borate and causing said metaorate to o in solution, and removing the solution rom the deposit.

In testimony whereof I have signed my as name to this specification.

HENRY BLUMENBERG, J B. 

